A Treatise Concerning the Principles of Human Knowledge. Wherein the Chief Causes of Error and Difficulty in the Sciences, with the Grounds of Scepticism, Atheism, and Irreligion, are inquired into. First Printed in the Year 1710. To which are added Three Dialogues Between Hylas and Philonus, In Opposition to Scepticks and Atheists. First Printed in the Year 1713. Both written by George Berkeley, M. A. Fellow of Trinity-College, Dublin